Well, it’s not necessary to quit avast.setup process (unfinished update process) but, sure, you have to configure your firewall and proxy settings (if any) to update.
Earlier versions of avast have problems with automatic detect IE settings but not in the last one (at least for me).
Can’t you update even manually?
Did you set the way you connect the Internet into avast settings?
If you need to learn anything about avast4.ini file, check my ‘Settings’ on the signature 